Remote code execution via malformed UTF-8 names
Published Feb 16, 2022 · Updated May 5, 2025
Improper UTF-8 validation in Expat before 2.4.5 allows remote attackers to execute arbitrary code via malformed XML input. Name-tokenization paths in xmltok_impl.c test multibyte sequences as XML name characters without first rejecting invalid encodings, allowing malformed two- and three-byte UTF-8 sequences to pass as tag names. Exposure requires an application to parse attacker-controlled XML with the affected library, and successful exploitation executes code in that application's process context.
Summary
What happened
Improper UTF-8 validation in Expat before 2.4.5 allows remote attackers to execute arbitrary code via malformed XML input. Name-tokenization paths in xmltok_impl.c test multibyte sequences as XML name characters without first rejecting invalid encodings, allowing malformed two- and three-byte UTF-8 sequences to pass as tag names. Exposure requires an application to parse attacker-controlled XML with the affected library, and successful exploitation executes code in that application's process context.
The record
- CVE
- CVE-2022-25235
- Published
- Feb 16, 2022
- Updated
- May 5, 2025
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-116
- Attack vector
- Unavailable
- Privileges
- Unavailable
Timeline
How it unfolded
- Feb 16, 2022CVE publishedPublication date reported by the CVE source.
- May 5, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo